Method and apparatus for stabilizing submersible vessels



July 21, 1959 .J. T. HAYWARD METHOD AND APPARATUS FOR STABILIZING SUBMERSIBLE VESSELS Filed July 22, 1953 2 Sheets-Sheet 2 (Jo/7n 7. Hayward INVENTOR.

A r fO/ffNf Y United States Patent METHOD AND APPARATUS FOR STABILIZING SUBMERSIBLE VESSELS John T. Hayward, Tulsa, Okla. Application July 22, 1953, Serial No. 369,633 '11 Claims. (Cl. 61-465) This invention relates to submersible vessels and methods for stabilizing such vessels during the submersion and raising thereof in a water body.

This invention is directed particularly to improvements in submersible drilling barges and methods of stabilizing during submersion and raising.

In my US. Patents Nos. 2,540,878 and 2,551,375,I have disclosed improved types of submersible drilling barges and methods and means for effectively stabilizing them during the submersion and raising operations, and the present invention is directed to improvements in such structures and methods.

Drilling barges and marine structures of the type described in the afore-mentioned patents are designed particularly for drilling oil wells in open ocean areas, such as in the so-called tide lands areas along the coast of the Gulf of Mexico and of California.

Such barges have proven very successful for such service due to the (fact that the hulls'are completely submerged-under the surface of the water and rest on the under-lying land bottom, the derrick being mounted on a'platform which is elevated above the deck of the hull at a height such that the derrick floor and the equipment,

mounted thereon, will [be above the tops of the waves which might be encountered in open ocean areas. As much of the drilling machinery and equipment as possible will be located in the hulls as it is desirable to keep the weight off the platform.

As pointed out in the afore-mentioned patents, a critical factor in effecting submersion and re-floating of such barges is the maintenance of complete nautical stability at the instant the hull deck comes awash, either in submersion or re-fioating, for at that critical stage, the hull tends to lose all stability and may turn turtle unless effective means for controlling the stability, at that stage of operations, is provided.

My former patents disclose means and methods for maintaining such stability and while these have proven entirely satisfactory, the improvements contemplated by .the present invention are directed to other and even more efiective means for assuring the desired degree of stability, particularly when operating in relatively deep water, [for example, in fifty feet or more of water,

. The problem of maintaining stability is greatly accentuated by the fact that the molded depth of the hull for use in such depths may be only 10 to 12 feet, while the super-structure supportingthe derrick platform will thereby extend 50 to feet or more above the hull deck and-will have superimposed thereon a conventional drilling derrick which may extend upwardly an additional or feet. For example, drilling barges constructed in accordance with this invention are approximately 230 feet long by 74 feet wide, with a hull depth of so-called turtle-back shape of from 8 to 14 feet. Such a hull will draw about 6 feet of water when afloat and fully loaded, and will support thereon a platform from 60 to 70 feet above the hull deck with the derrick on top of that so that the top of the derrick will be approximately 2,895,300 Patented July 21, 1959 220 to 230 feet above the surface of the water when the barge is afloat. It is obvious that any failure to maintain complete nautical stability could quickly be disastrous in moving such a structure from the surface to the bottom and from the bottom to the surface, although the structure may be fully stable while it is afloat.

In accordance with the present invention, I accomplish the desired degree of stabilization by the employment of one or more stabilizing bodies positioned in laterally spaced relation to the sides of the vessel. Such stabilizing bodies are pivotally connected to the sides of the vessel so that the vessel may be raised or lowered through the water relative to the stabilizing bodies, the latter being constructed to have negative buoyancy and to be maintained partially submerged in the water body while the vessel is being submerged or re-floated. I have found that by the use of such stabilizing bodies, having negative buoyancy and suitably connected to the vessel, complete stability of the vessel may be maintained under all conditions during submersion and re-floating.

Such stabilizing bodies may be in the form of pontoonlike members having shape and dimensions such as to have substantial displacement and to define a water plane of substantial area. The pontoon members may be filled with water or other ballast sufficient to impart to the body negative buoyancy. A boom or other rigid arm member extending laterally from the vessel is connected at one end to the stabilizing body and has its other end pivotally or hingedly connected to the side of the vessel. The negatively buoyant body is then maintained in partially submerged position at all times by means of an adjustable support arm, which may be a cable or the like, which extends from the stabilizing body to another point on the vessel structure vertically spaced from the point of connection of the pivoted arm, the support being also arranged to form a pivoted connection between the sta bilizing body and the vessel.

By such an arrangement, it is found that if the negatively buoyant body is maintained in partiallysubmerged condition so as to have a substantial Water plane, the vessel may be safely submerged and re-fioated. It should be emphasized that the important feature of this invention is the employment Oif a negatively buoyant body which is positioned in the water laterally spaced from the vessel and which is so connected to the vessel that it may be maintained partially submerged throughout the raising and lowering of the vessel relative thereto.

Other and more specific objects and advantages of this invention will become apparent from the following detailed description when read in conjunction with the accompanying drawing, which illustrates, more or less schematically, a useful embodiment in accordance with the present invention.

In the drawing:

Fig. l is a side elevational view showing a drilling barge fitted with stabilizing means constructed and operated in accordance with the principles of this invention and shown in floating position on a water body;

Fig. 2 is a partial end view of the barge in the floating position illustrated in Fig. l;

Fig/2i: is a view similar to Fig. 2 showing relative positions of the barge structure and the stabilizingbody at one stage in the descent of the hull below the surface of the water body;

Fig. 3 is a fragmentary top view illustrating an arrangement for stowing the stabilizing body in the super.- structure when the stabilizing body is not in use;

Fig. 4 is a partly sectional elevation taken generally along line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 3, but showing the stabilizing body in laterally extended stabilizing .position; Q t an;

Fig. 6 is an end elevation taken along lines 6-6 of Fig. and illustrating two positions of the stabilizing body relative to the hull and super-structure when the hull is positioned on the land bottom; and

Fig. 7 is a longitudinal sectional view of the stabilizing body taken generally along line 7-7 of Fig. 5.

For purposes of this description and the claims, the term vesse'will be employed to include the hull together with the super-structure imposed thereon.

Referring to the drawing, a drilling barge is shown which comprises a hull ll) of elongated generally rectangular, hollow, box-like shape, having a flat bottom 11 and a deck 12 which may be flat or may be convex, such as one of the forms illustrated in my Patent No. 2,551,375. It will be understood that hull will be suitably compartmented and provided with generally conventional ballast handling equipment by which the hull may be efiiciently ballasted or de-ballasted for submersion and raising. Mounted on the hull is a super-structure, designated generally by the numeral 13, which comprises a plurality of appropriately spaced vertically disposed columns 14, which are preferably round and of fairly large diameter, the upper ends of which support a platform, designated generally by the numeral 15, on top of which may be mounted a drilling derrick 16 and appurtenant drilling devices, the details of which do not form a part of the present invention. As illustrated, platform may comprise upper and lower decks or floors 17 and 18, respectively, the upper floor 17 being supported at any desired elevation above lower floor 18 by means of columns 1?. The space between the floors may be employed to house drilling and operating machinery and the like. It will be understood that the lengths of columns will be made such that platform 15 will be at a suitable height above the mean water level W when hull it is resting on the underlying land, so that any waves will pass through the structure beneath platform 15. Columns 14 will preferably be made of such size and strength that a minimum number will be required to support the maximum load represented by platform 15 and the equipment thereon. By employing a comparatively few widely spaced, round columns, a maximum degree of wave transparency of the hull structure will be provided when the structure is resting on the land bottom.

Disposed in laterally spaced relation to the hull is a stabilizing body 20 which may be in the form illustrated more specifically in Fig. 7; that is, it may be an elongated box-like casing 21 which is closed on all sides and may i be provided with one or more bulkheads 22 arranged to partition the interior thereof into a plurality of compartments 2323. The compartments 23 may be provided with valves or sea chests 24 which open through the bottom wall of the casing and which are provided with operating stems 25 extending through the upper deck of the casing by which the sea chests may be opened or closed, as desired. It will be understood that by opening the sea chests 24 and immersing casing 21 in the water body, water will flow into the compartments and fill them to the extent desired.

A boom or arm member, designated generally by the numeral 26 is provided to pivotally connect casing 21 to the side of the vessel to permit relative vertical movement between the vessel and casing 21. The arm member 26 may be of any suitable construction which will provide a rigid arm pivotally connecting the stabilizing member to the vessel. As illustrated, arm member 26 is constructed in the form of a pair of parallel, generally horizontal trusses, each truss being composed of side stringers 27-27 inter-connected by cross-bracing members 28-28, as best seen in Figs. 1 and 5. Each of the trusses is pivotally connected at 29 to the side of the vessel. The point of connection may conveniently be to adjacent ones of the columns 14, as shown. The opposite ends of the trusses are likewise pivotally connected at 30 to the opposite ends of casing 21. The

4 3 parallel truss arrangement having pivoted connection both to the vessel and to the casing, is a convenient arrangement for maintaining the deck of casing 21 in a horizontal position while the vessel moves vertically relative thereto. It will be understood, however, that a single rigid arm, instead of the compound truss structure, may be employed to pivotally connect casing 21 to the vessel, and for purposes of this invention it is not essential that there be a pivotal connection between the boom or arm member and the stabilizing body. It is only necessary that there be a pivotal connection between the arm member and the vessel. It will also be understood that the pivot point on the vessel may be located on the hull itself or at any point along the super-structure, as may be dictated by most efiicient design considerations. As illustrated, the pivot is positioned at a point along coltunns 14 intermediate the hull and platform.

A cable 31 is strung between a multi-sheave pulley block 32 attached to the top of casing 21 and a second multi-sheave block 33 mounted on the platform; for example, on floor 18. The live end of the cable leads to a power winch 34 of any suitable form, by which the length of the cable may be adjusted to raise or lower casing 21, or to maintain it in a more or less stationary position in the water while the vessel is raised or lowered relative thereto. A slot or bay 35 may be provided in floor 18 to receive the casing 21 for stowing when it is not required, as will be more fully described hereinafter.

The above described structure may be operated in the following manner: Referring first to Fig. 1, the vessel is shown in the position which it normally occupies when afloat, as when being towed through the water from one location to another, the water level being indicated by the line W. When the structure is thus afloat, it will ordinarily be stable and the stabilizing body may or may not be positioned in the water at the time, although if disposed in the water, as illustrated in Figs. 1 and 2, the body will add to the stability of the structure while afloat. If not needed or not used for this purpose, the stabilizing body may be swung into bay 35 by means of winch 34 and cable 31 to the position illustrated in Fig. 4. This will ordinarily be the case when the vessel is in movement from one place to another in order to reduce the over-all width of the structure for navigating narrow channels, or for docking.

When a location at which drilling is to be conducted has been reached, the stabilizing body 20 will be lowered into the water. Sea chests 24 will then be opened and water allowed to flow into the interior of casing 21 until a sufiicient quantity of ballast has been admitted to render casing 21 negatively buoyant when totally submerged, whereupon the sea chests will be closed to maintain the negative buoyancy of the body. Cable 31 will then be adjusted sufiiciently to maintain the body at the desired water line, as indicated in Figs. 1 and 2. Since casing 21 is negatively buoyant, cable 31 will remain taut at all times because of the weight of the ballasted casing. With stabilizing body 20 partially submerged, it will have by reason of its geometry, substantial displacement and a water plane of substantial area, the water plane of intersection by the water level W. Hull 10 will then be ballasted in the conventional manner, as by admitting sea water to a suitable number of compartments therein, in order to destroy its buoyancy and allow the hull structure to descend toward the underlying land, indicated at L. As the hull descends, cable 31 will be adjusted in length to continuously maintain body 20 in the partially submerged condition in order to maintain the water plane of the body. The body 20 will swing about pivots 29 as the hull structure descends relatively thereto. The partially submerged condition of body 20 and maintenance of the water plane provided thereby will be continued until hull 10 comes to rest on the land bottom and attains the position shown in submerged Condition, the vessel will remain completely nauticallystable after the upper deck of the hull comes awash in its descent. This, as previously noted, being the critical stage durmg which stability must be assured .during submergence and re-floating of the hull.

When the, hull has landed on bottom, body 20 may be swung to its stowage position in bay 35, as shown in Figs. 3 and 4; or if desired, cable 31 may be extended to allow body 20 to descend to the land bottom, as illustrated in broken lines in Fig. 6. In the latter operation,

'by so disposing the body 20 alongside the hull on bottom,

body 20 will act to protect the hull from undercutting by water currents and will assist in stabilizing the structure while it is on bottom.

To re-float the vessel, the above described operations are reversed. Starting from the on bottom position, shown in Fig. 6, hull will be de-ballasted to render it buoyant and as it ascends stabilizing body will be maintained in the partly submerged condition, shown inthe full lines in Fig, 6, throughout the raising operation, until the hull; has againbeen raised to the floating position, illustratedin Figs, 1 and 2. As the hull rises, cable 31 will be let out sufficiently to adjust for the change in relative positions of the vessel and stabilizing body. l a

When the stabilizing body 20 is to be raised to the stowage position, shown in Figs. 3 and 4, it will be understood that sea chests 24 may be opened and as the body is raised the ballast will be emptied out of casing 21, thereby greatly reducing the weight of the stabilizing body as it is raised to its stowage position.

It will be understood that although only one stabilizing body is illustrated, a similar stabilizing body may be similarly mounted on the opposite of the vessel, although for the purpose of stabilizing the vessel it is not essential that more than one stabilizing body be employed, as the vessel may be safely stabilized by using only one of the stabilizing bodies. The use of two stabilizers on opposite sides of the vessel will ordinarily be preferable for purposes of more symmetrical load distribution and somewhat easier control.

The stabilizing influence of body 20 will be proportional to the area of its water plane and to the moment of inertia of this water plane about the center line of the vessel. Accordingly, the transverse cross-sectional area of body 20 and the length of arm member 26 may be varied widely depending upon the degree of stabilization desired for the particular vessel. In general, the stabilizing body may have a negative buoyancy of the order of 10 to 20% of its displacement, although this particular value is not critical so long as the body 20 has definitely negative buoyancy.

It will be understood that the particular shape or construction of body 20 may vary widely; in fact, body 20 may even be a solid object or it may be a hollow body ballasted with solid material, such as sand or the like. However, a hollow casing or pontoon construction, as described, will usually be preferable as it is obvious that ballast to render it negatively buoyant will be most conveniently provided by the water in which it is immersed. As noted previously, the dimensions of body 20 may vary widely, so long as its geometry is such as to provide suitable displacement and water plane area. Merely by way of illustration, in connection with a drilling barge structure of the dimensions given above, body 20 may conveniently be made 50 long by 10 wide and 6 deep. This will provide a Water plane of 500 square feet and a displacement, when filled with water, amounting approximately to 100 tons.

By making body 20 negatively buoyant, cable 31 will at all times remain taut, as noted, and thereby will not be afiected by wave action or other surface water movements.

with its sheave block connections to stabilizing body 20 and to the vessel, constitutes a pivoted support arm extending between body 20 and the vessel, having pivoted connection to the vessel at a point vertically spaced from the point of connection of arm member 26 to the vessel. Thus body 20 is, in elfect, pivotally connected to the vessel at vertically spaced points by a pair of arm members, one of which is of rigid construction and the other adjustable in length, being thereby adapted to continuously support body 20 in partially submerged position in the water while compensating for changm in elevation of the vessel relative to body 20 during submersion and re-fioating of the vessel.

It will be understood that numerous alterations and changes may be made in the details of the illustrative embodiment within the spirit of the invention but without departing from the scope of the appended claims.

What I claim and desire to secure by Letters Patent stabilizing body in laterally spaced relation to the vessel,

and maintaining said stabilizing body While negatively buoyant partially submerged in the water body as the vessel descends and emerges through the surface of said water body. f

2."A method for stabilizing a submersible vessel during the submersion and raising thereof in a water body, comprising, pivotally connecting a negatively buoyant stabilizing body to one point on the side of the vessel in laterally spaced relation thereto, supporting said stabilizing body while negatively buoyant in partly submerged condition in the water body from a second point on the vessel vertically spaced from said one point, and lowering and raising the vessel through the water body relative to the stabilizing body while the latter is maintained in said partly submerged negatively buoyant condition.

3. A method for stabilizing a submersible vessel during the submersion and raising thereof in a water body, comprising, pivotally connecting a pair of negatively buoyant stabilizing bodies to opposite sides of the vessel in laterally spaced relation thereto, and maintaining said stabilizing bodies while negatively buoyant partially submerged in the water body as the vessel descends and emerges through the surface of said water body.

4. A method for stbilizing a submersible vessel during submersion and raising thereof in a water body, comprising, pivotally connecting a negatively buoyant stabilizing body to one point on the side of the vessel in laterally spaced relation thereto, connecting said stabilizing body to a second point on the side of said vessel vertically spaced from said one point by a support connection of adjustable length, and adjusting the length of said support connection in accordance with the vertical movement of the vessel relative to said stabilizing body to thereby maintain said stabilizing body while negatively buoyant in partly submerged condition in the water body as the vessel descends and emerges through the surface of said water body.

5. Apparatus for stabilizing a submersible vessel during submersion and raising thereof in a water body, comprising, a stabilizing body having negative buoyancy positioned partly submerged in the 'water body in laterally spaced relation to the vessel, and means pivotally connecting the stabilizing body to the vessel constructed and arranged to maintain the stabilizing body partly submerged in the water body during submersion and raising of the vessel.

6. Apparatus for stabilizing a submersible vessel during submersion and raising thereof in a water body, comprising, a stabilizing body having negative buoyancy positioned partly submerged in the water body in laterally spaced relation to the vessel, a pair of connection membars pivotally connecting said stabilizing body to vertically spaced points on the vessel, one of said connection members being adjustable .in length to maintain said stabilizing body partly submerged in the water body during submersion and raising of the vessel.

7. Apparatus for stabilizing a submersible vessel during submersion and raising thereof in a water body, comprising, a stabilizing body having negative buoyancy positioned partly submerged in the water body in laterally spaced relation to the vessel, a pair of connection members pivotally connecting said stabilizing body to vertically spaced points on the vessel, the lower one of said members being of substantially rigid construction, and the upper one of said members being adjustable in length to maintain said stabilizing body partly submerged in the Water body during submersion and raising of the vessel.

8. Apparatus for stabilizing a submersible vessel during submersion and raising thereof in a water body, comprising, a stabilizing body having negative buoyancy positioned partly submerged in the water body in laterally spaced relation to the vessel, said stabilizing body having substantial displacement and geometrical shape such as to provide a water plane of substantial area when partly submerged in the water body, and means pivotally connecting the stabilizing body to the vessel, said means being constructed and arranged to maintain the stabilizing body partly submerged in the Water body during submersion and raising of the vessel.

9. Apparatus according to claim 8 wherein said means comprises a pair of connection memberspivotally connecting said stabilizing body to vertically spaced points on the vessel, one of said members being adjustable in length. 7

10. Apparatus according to. claim 8, wherein said means comprises a pair of connection members pivotally connecting said stabilizing body to vertically spaced points on the vessel, the lower one of said members being of substantially rigid construction and the upper one of said members comprising a flexible cable adjustable in length.

11. Apparatus according to claim 8, wherein said stabilizing body comprises a box-like hollow casing having means for admitting ballast therein.

References Cited in the file of this patent UNITED STATES PATENTS 545,095 Redmond Aug. 27, 1895 1,681,533 Giliasso Aug. 21, 1928 2,066,150 Hort Dec. 29, 1936 2,525,955 Scott Oct. 17, 1950 OTHER REFERENCES World Oil of Feb. 1, 1950, pp. 108, 110, 112. 

